build script that uses docker container (#1944)

old-commit-hash: e4720eb798

tools/README.md

@@ -31,6 +31,7 @@ Setup
 1. Run `ubuntu_setup.sh` or `mac_setup.sh`, make sure everything completed correctly
 
 2. Compile openpilot by running ```scons``` in the openpilot directory
+   or alternatively run ```./openpilot_build.sh``` (uses a pre-configured docker container)
 
 3. Try out some tools!
 

tools/openpilot_build.sh

@@ -0,0 +1 @@
+docker run --rm -v $(pwd):/tmp/openpilot -it commaai/openpilot bash -c 'cd /tmp/openpilot && scons -j$(nproc)'